Effect of alpha-linolenic acid on blood glucose, insulin and GLUT4 protein content of type 2 diabetic mice

Alpha-linolenic acid (LL) was tested for antidiabetic activity in KK-Ay mice, an animal model of type 2 diabetes. Repeated administration of LL (300 mg/ kg) to KK-Ay mice significantly suppressed the increment of blood glucose at 21 d (p<0.05). However, no affect on the blood glucose level in normal mice was seen, indicating that LL is useful in treating type 2 diabetes. In addition, LL improved hyperinsulinemia in KK-Ay mice (p<0.01). LL also significantly decreased the blood glucose at 120 min in the insulin tolerance test (p<0.05). The muscle content of facilitative glucose transporter isoform 4 (GLUT4) protein content in the total membrane fraction from KK-Ay mouse muscle significantly increased in the LL-treated mice when compared to that in the controls (p<0.01). From these findings, it seems likely that the hypoglycemic effect of LL is derived, at least in part, from the decrease in insulin resistance, due presumably to the increase of GLUT4 protein content in total membrane of the muscle.